Great write up ...this means there is hope for a fix. So just because no leak can be seen from the outside of the bellhousing doesn't mean an internal leak hasn't contaminated the clutches causing damage and all the shuddering issues. So we should have our clutch packs pulled and inspected and not just the outer bellhousing inspected. Wonder how hard it will be to convince the service dept to do this? Your post helps and I'm sure will be used by many to get this looked at.

This.

I have the clutch chattering but no leaking on the outside (I checked myself). Because there's no leak, the service department never checked my clutches. I'm taking it in on Monday for a test drive, this time with their transmission technician now that I can consistently duplicate the chattering.